1. Technical Field
The present invention is directed toward an improved method and system for first finding all aircraft flying on inefficient routes, then determining whether it is possible to save time by bypassing some route segments, and finally determining whether the improved route is free of conflicts with other aircraft. In particular, the present invention relates to automatically identifying all aircraft eligible for direct-to routes and to determine and display the corresponding timesaving.
2. Description of the Related Art
In recent years, advances in air traffic control have often been evaluated by how effectively they further the goals of "free flight." Although the notion of free flight is difficult to define precisely, any method that reduces constraints and increases the freedom of airspace users to operate aircraft in a manner they consider optimum is considered to be a step toward free flight. Since the notion became popular a number of years ago, numerous innovations, technologies and automation methods have been investigated under the umbrella of free flight. Some of these were recommended for national development by a consensus of airspace users, operators and air traffic control experts. In response to these recommendations, the Federal Aviation Administration established the Free Flight Project Office to lead and execute a deployment effort.
This development effort consisted of evaluating a Conflict Probe/Trial Planner (CPTP) built into the Center TRACON Automation Systems (CTAS) used by air traffic controllers. During the field test of CPTP at the Denver Air-Traffic Control Center, air traffic controllers would usually attempt to resolve conflicts predicted by the CPTP by trial-planning resolution trajectories that led from the conflict aircraft's current position to a down-stream fix along the aircraft's flight plan. In about 20 percent of such attempts, they succeeded in finding trajectories direct to a fix that resolved the conflict. Thus, when this method was successful, the solution had the additional advantage of reducing the path distance to fly to the destination. In the Denver Air Traffic Control Center tests, only aircraft that were "fortunate" to have been identified as being in conflict had the potential to benefit from path shortening direct-to fix trajectories. This finding suggested the following hypothesis: Since conflicts are random events, there must exist a similar percentage of non-conflict aircraft that could reduce their path distances by direct-to fix trajectories. Armed with this knowledge, air-traffic controllers at a follow-on test of CPTP at the Fort Worth Air Traffic Control Center used the Trial Planner to manually search for non-conflict aircraft that could benefit from direct-to fix trajectories. Through trial and error with CPTP they found many aircraft, especially departures from DFW airport, that were eligible for path shortening direct-to fix trajectories.
While effective for finding and resolving conflicts and conflict probing direct routes for any aircraft selected by the controller, CPTP lacked the ability to automatically identify each and every aircraft eligible for direct-to routes and to determine and display the corresponding time savings. To aircraft operators, time saving, which accounts for the effect of winds, and not necessarily path length saving is the appropriate measure of flight efficiency. Therefore, a need exists for adequately and efficiently by an automatic method, identifying all aircraft eligible for direct-to routes and to determine and display the corresponding timesaving. More particularly, a method must be provided to account for the effect of wind patterns in determining whether direct-to routes reduce the time to fly. The subject invention herein, solves these problems in a unique and novel manner not previously known in the art.